Is the Sun Prolonging the Effects of Deepwater Horizon?

A new study from the Woods Hole Oceanographic Institution in Massachusetts, USA has found that oxygenated hydrocarbons resulting from the Deepwater Horizon oil spill in 2010 are showing little sign of breaking down in the environment. The research, published in the journal Environmental Science and Technology, suggests that sunlight might be exacerbating the effects of the oil spill and making it harder to clean up.

What was the Deepwater Horizon oil spill?

Eight years ago, an offshore drilling rig named Deepwater Horizon and positioned in the Gulf of Mexico was guilty of the biggest oil spill in US territory in history. The rig had been built by South Korean firm Hyundai Heavy Industries and leased to oil tycoons BP, but on the 20^th April 2010, an unforeseen complication caused an explosion on the rig.

The detonation claimed the lives of 11 rig workers and sparked an inferno that was visible as far as 40 miles away. After raging for two days, the fire finally sank the rig and the oil contained within was spilled into the neighbouring waters, resulting in a massive environmental disaster and a huge clean-up operation.

Nature exacerbating the problem

In the past, it has been suggested that nature could serve as a potential ally in clearing up oil spills, with plants being used to soak up unwanted oil from the water and expedite the cleansing process. However, nature appears to have worked against human interest in the case of Deepwater, as light from the sun has reacted with the oil to create unusually durable hydrocarbons in the water.

The discovery was made by a team of scientists analysing the soup of contaminants in and around the Gulf of Mexico, including the concentration of contaminants found on nearby beaches. To their surprise, they found that over 50% of the residue from the oil spill was comprised of oxygenated hydrocarbons, created when the sun reacted with the oil molecules. The fact that all of the samples showed more or less the same levels of hydrocarbon contamination suggests they have not broken down at all in the intervening eight years.

What next?

At present, the scientists do not know how dangerous these persistent hydrocarbons can be. Christopher Reddy, one of the chemists behind the study, says that it is very difficult to test levels of toxicity in the residue, since the exact composition of the contaminants varies from place to place. It’s also difficult to know whether these pollutants will pose a risk to marine life, as well.

With the scientific community still not in agreement over the best way to clean up flooded lakes and reservoirs, the news that sunlight can exacerbate oil spills means there is one more aspect of  contamination to take into consideration. However, it’s clear that further research is required before any definitive pronouncement on the gravity of these hydrocarbons can be made.